The present invention relates to soles for use with articles of footwear. More particularly, the present invention relates to soles having a plurality of bulbous protrusions and providing pneumatic ventilation to the foot.
Since man has begun wearing shoes to protect his feet, he has continually strived for increased comfort. Not surprisingly, his efforts have been continually directed toward improvements in the sole of the shoe. Efforts to improve the sole of the shoe have included softer materials, anatomical shapes, and means for aerating the feet. However for the most part, these efforts have remained isolated from one another.
Various patents have sought to aerate the feet through a plurality of channels interspersed within the shoe sole. A representative example is Batra, U.S. Pat. No. 4,617,745 in which air channels provide a flow of air to the foot through a multiplicity of holes. While an air inlet is provided at the instep of the sole, no means other than the placement of the air inlet is provided for resisting contamination from water or dirt. The French patent to Pradet, French Patent No. 1,432,811 incorporates a different canal design while encountering similar problems.
Various patents have also attempted to provide sufficient flexibility and resiliency in a shoe sole through the incorporation of air chambers. Vermeulen, U.S. Pat. No. 4,223,455 discloses a plurality of air chambers having a generally round configuration. Parker et al., U.S. Pat. No. 4,817,304 discloses a cushioning sole structure including a sealed inner member inflated with a gaseous medium. These types of air chambers generally provide support to the foot but fail to provide a means for aerating the foot. Additionally, these types of air chambers are quite complicated and difficult to manufacture.
Some patents have attempted to massage the foot or provide increased health through the strategic placement of undulating tabs. Turucz, U.S. Pat. No. 4,841,647 discloses a plurality of convex tabs to massage the soles of the feet during walking. These tabs correspond to the acupressure zones of the foot. The German patent to Ellrich, DE 33,30,060,A1 discloses a plurality of sole inserts consisting of two different metals. Under contact with perspiration, the two metals provide therapeutic properties due to galvanic action. Patents such as these fail to provide adequate aeration of the feet and also fail to take advantage of the latest materials.
A few patents have attempted to combine a means for aeration along with massaging support columns. Biasi, U.S. Pat. No. 5,035,068 discloses a plurality of compressible support columns to stimulate the lower portions of the wearer's foot. A pair of collapsible valves allow air to be forced through the spaced columns and then through a perforated anatomical sock. Biasi, however, fails to provide a means for preventing liquid from entering the pair of collapsible valves.
Goller, U.S. Pat. No. 4,910,882 discloses an aerating and massaging insole which combines a plurality of ribs with a perforated base. While contact of the foot with the ribs seeks to massage the foot, air may penetrate the perforated base. Goller does not provide a means for fresh air to enter the shoe cavity. Although Goller and Biasi seek to provide a massaging action to the foot, the effectiveness of this action is compromised by the insertion of a perforated layer above the massaging means.
Pon-Tzu, U.S. Pat. No. 4,760,651 discloses a shoe pad having an air blowing compression chamber which connects to the external air by a modified permanent shoe horn. Convex grains having a circular shape are disposed on the top of the shoe pad to massage the foot and separate the wearer's foot from the shoe pad. However, this shoe pad is designed to retrofit an existing shoe structure and does not appear to communicate air from the shoe sole directly to an ambient air source.